1. Field of the Invention
This invention concerns cutting devices for cutting cardboard and the like and in particular to a cutting device commonly referred to as a mount cutter for cutting an aperture in a cardboard mount used for framing a picture or photograph. The cutting device in a mount cutter is arranged so that the edge of the aperture cut in the cardboard mount is inclined to the surface of the mount by an angle which is not equal to 90.degree.. The object is to provide a bevelled edge to the aperture which is visible when the picture or photograph is viewed, the function of the bevelling being to give a feeling of depth when the picture or photograph is viewed.
2. Description of the Prior Art
A mount cutter is known such as that disclosed in U.S. Pat. No. 3,213,736 to William B. Keeton, in which a cutting blade is carried by a first housing member which is pivotally joined to a second housing member the latter being slidable along a rail which is in practice arranged parallel to the desired direction of cut. The pivot joint between the first and second housing members allows the blade to be lowered into contact with an inclined guide face located parallel to the rail and into the mount at the beginning of a cut and, after the cut has been made to be raised clear of the cut at the far end. However the pivot joint is subjected in use to not inconsiderable shear forces and wear at the bearing surfaces results in misalignment of the blade relative to the guide face. The wear at the pivot joint is cumulative with any wear which occurs between the second housing and the rail and the total effect can be considerable after this known mount cutter has been in use for some time.